Method for determining silicate content in salt lake brine
By using boron-removing adsorption resin and imprinted hydrogel to remove impurities in salt lake brine, and then combining this with Raman spectroscopy for determination, the problems of large reagent consumption and low detection accuracy in existing technologies have been solved, enabling rapid and accurate determination of silicate content in salt lake brine.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2023-03-07
- Publication Date
- 2026-03-17
AI Technical Summary
Existing technologies for determining silicate content in salt lake brine require large amounts of reagents, have low accuracy, and are easily affected by factors such as ambient temperature, color development time, and acidity.
Boric acid, borates, and metal cations in salt lake brine were removed using boron-removing adsorption resin and imprinted hydrogel, and then measured using Raman spectroscopy. The coffee ring effect and high-resolution detection were utilized to simplify reagent dosage and improve accuracy.
This method enables rapid and accurate determination of silicate content in salt lake brine, reduces reagent consumption and environmental interference, and improves the accuracy of test results.
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Figure BDA0004113283170000051
Abstract
Description
Technical Field
[0001] This invention relates to the field of salt lake brine detection technology, and more specifically, to a method for determining the silicate content in salt lake brine. Background Technology
[0002] A salt lake is a saline body of water, generally referring to a lake with a salinity w(NaCleq) > 3.5% (greater than the average salinity of seawater). Salt lake brines are rich in mineral resources such as potassium salts and rare metals. Accurate analysis of the content of various components in salt lake brines is very important for accelerating the comprehensive utilization and development of salt lake resources.
[0003] Currently, when determining the silicon content in salt lake brine, most methods refer to Part 4 of the "Marine Monitoring Standard" (GB 17378.4-2007): Determination of Silicates in Seawater Analysis - Silicate Molybdate Yellow Spectrophotometric Method. This method has drawbacks, including cumbersome operation steps, long operation time, the need for a large number of chemical reagents such as sodium chloride, magnesium sulfate, and ammonium molybdate, and susceptibility to interference from environmental temperature, color development time, acidity, and other factors, which can affect the measurement results. Summary of the Invention
[0004] The main objective of this invention is to provide a method for determining the silicate content in salt lake brine, thereby solving the problems of large reagent consumption and low accuracy of detection results in the prior art when determining the silicate content in salt lake brine.
[0005] To achieve the above objective, according to one aspect of the present invention, a method for determining the silicate content in salt lake brine is provided, comprising the following steps: Step S1, obtaining the salt lake brine to be tested, and sequentially passing it through a boron removal adsorption resin and an imprinted hydrogel to remove boric acid, borate, and sodium chloride from the salt lake brine to be tested. + Other than metal cations, a test solution is obtained; Step S2, a standard salinity matrix with the same salinity value as the test solution is prepared, and different volumes of silicate standard solution are added to the standard salinity matrix to obtain multiple control solutions with different silicate mass concentrations; Step S3, the control solutions are dropped onto the substrate, evaporated at room temperature to obtain multiple control coffee rings, and the multiple control coffee rings are scanned using a Raman spectrometer to obtain multiple control Raman spectra. Based on the silicate mass concentration of the control solutions and the peak area of their Raman spectra, a linear regression equation is obtained; Step S4, the test solution is dropped onto the substrate, evaporated at room temperature to obtain the test coffee ring, and the test coffee ring is scanned using a Raman spectrometer to obtain the test Raman spectrum. The peak area of the test Raman spectrum is substituted into the linear regression equation to obtain the silicate content in the salt lake brine to be tested.
[0006] Further, in step S1, boric acid and borates in the brine to be tested are first removed using a boron-removing adsorption resin, and then metal cations in the brine to be tested are removed using an imprinted hydrogel with metal cations as template molecules. The metal cations include Li + K + Ca 2+ Mg 2+ 、Sr 2+ and Rb + .
[0007] Furthermore, in step S1, the boron removal adsorption resin is CH-99 boron removal adsorption resin.
[0008] Further, in step S2, the method for preparing the standard salinity matrix is as follows: first, the salinity value of the solution to be tested and the content of salt components therein are determined, and then the standard salinity matrix is prepared using water and salt components of the same content.
[0009] Further, in step S2, the method for preparing the silicate standard solution is as follows: the silicate standard solution is prepared by using the estimated silicate mass concentration of the brine to be tested as the concentration of the silicate standard solution.
[0010] Further, in step S2, the preparation method of the control solution is as follows: 10 ml, 20 ml, 30 ml, 40 ml, and 50 ml of silicate standard solution are added to the standard salinity matrix respectively to obtain control solution 1, control solution 2, control solution 3, control solution 4, and control solution 5 with silicate mass concentrations of 20 μg / mL, 40 μg / mL, 60 μg / mL, 80 μg / mL, and 100 μg / mL respectively.
[0011] Furthermore, in step S3, the linear regression equation uses the silicate mass concentration of the control solution as the abscissa and the peak area of its Raman spectrum as the ordinate.
[0012] Furthermore, the substrate is a gold-plated glass slide, a molybdenum mirror, a stainless steel sheet, or an aluminum sheet.
[0013] Furthermore, the detection parameters of the Raman spectrometer are as follows: laser source is 785nm, laser power is 1200mW, exposure time is 1 second, and number of exposures is 25.
[0014] Furthermore, the Raman spectrometer operates in the range of 400–1250 cm⁻¹. -1 Scan within the displacement range.
[0015] By applying the technical solution of this invention, boric acid, borates, and metal cations in the brine of the salt lake to be tested are first removed using boron-removing adsorption resin and imprinted hydrogel. This reduces the interference of salinity and other substances on the detection results and simplifies the preparation process of the salinity matrix, while also reducing the amount of reagents used. Furthermore, it fully combines the separation and enrichment characteristics of the coffee ring effect with the high-resolution detection of Raman spectroscopy, enabling rapid and accurate determination of the silicate content range in the brine of the salt lake. Detailed Implementation
[0016] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. The present invention will now be described in detail with reference to the embodiments.
[0017] As described in the background section of this invention, existing technologies suffer from problems such as large reagent consumption and low accuracy in determining silicate content in salt lake brine. To address these issues, in a typical embodiment of this invention, a method for determining silicate content in salt lake brine is provided, comprising the following steps: Step S1, obtaining the salt lake brine to be tested, and sequentially passing it through a boron removal adsorption resin and an imprinted hydrogel to remove boric acid, borate, and sodium chloride from the brine. + Other than metal cations, a test solution is obtained; Step S2, a standard salinity matrix with the same salinity value as the test solution is prepared, and different volumes of silicate standard solution are added to the standard salinity matrix to obtain multiple control solutions with different silicate mass concentrations; Step S3, the control solutions are dropped onto the substrate, evaporated at room temperature to obtain multiple control coffee rings, and the multiple control coffee rings are scanned using a Raman spectrometer to obtain multiple control Raman spectra. Based on the silicate mass concentration of the control solutions and the peak area of their Raman spectra, a linear regression equation is obtained; Step S4, the test solution is dropped onto the substrate, evaporated at room temperature to obtain the test coffee ring, and the test coffee ring is scanned using a Raman spectrometer to obtain the test Raman spectrum. The peak area of the test Raman spectrum is substituted into the linear regression equation to obtain the silicate content in the salt lake brine to be tested.
[0018] This invention first removes boric acid, borate, and metal cations from the brine in the salt lake to be tested using a boron-removing adsorption resin and an imprinted hydrogel. This eliminates impurity ions that could affect subsequent silicate coffee ring effect or Raman spectroscopy measurements. This reduces interference from salinity and other substances on the detection results and simplifies the preparation process of the salinity matrix, reducing the amount of reagents used to obtain the test solution. Subsequently, a standard salinity matrix with the same salinity value as the test solution is prepared. Different volumes of silicate standard solution are added to the standard salinity matrix to obtain multiple control solutions with different silicate mass concentrations, which serve as references for subsequent silicate content determination. The method involves several steps: First, the control solution is dropped onto a substrate and evaporated at room temperature to obtain multiple control coffee rings. These control coffee rings are then scanned using a Raman spectrometer to obtain multiple control Raman spectra. Based on the silicate mass concentration of the control solutions and the peak area of their Raman spectra, a linear regression equation is obtained, which serves as the basis for determining the silicate content of the sample to be tested. Finally, the sample to be tested is measured. The test solution is dropped onto a substrate and evaporated at room temperature to obtain the test coffee rings. These test coffee rings are then scanned using a Raman spectrometer to obtain the test Raman spectrum. The peak area of the test Raman spectrum is substituted into the linear regression equation to obtain the silicate content in the brine of the salt lake. This method also fully combines the separation and enrichment characteristics of the coffee ring effect with the high-resolution detection of confocal micro Raman spectroscopy, enabling rapid and accurate determination of the silicate content range in salt lake brine.
[0019] Specifically, in a preferred embodiment, in step S1, boric acid and borate in the brine to be tested are first removed using a boron-removing adsorption resin, and then metal cations in the brine to be tested are removed using an imprinted hydrogel with metal cations as template molecules. The metal cations include Li. + K + Ca 2+ Mg 2+ 、Sr 2+ and Rb + Using metal cations as templates, metal ion-imprinted polymers are prepared using imprinting technology. This method exhibits higher selectivity and stronger recognition characteristics for template ions of metal cations, thereby enabling the selective removal of metal cations.
[0020] To further improve the removal effect of boric acid and borate, in a preferred embodiment, in step S1, the boron removal adsorption resin is CH-99 boron removal adsorption resin. The functional groups of the above resin have a stronger chelating effect with boron, resulting in better adsorption effect, larger surface area and greater surface activity, thus achieving better boron removal effect.
[0021] In a preferred embodiment, in step S2, the standard salinity matrix is prepared by first determining the salinity value of the solution to be tested and the content of its salt components, and then preparing the standard salinity matrix using water and the same amount of salt components. This operation can further eliminate the influence of the salt lake brine matrix on the determination of silicate content, thereby further improving the accuracy of silicate content determination.
[0022] In order to better match the composition and concentration of the control solution and the test solution, in a preferred embodiment, in step S2, the silicate standard solution is prepared by using the estimated silicate mass concentration of the brine in the salt lake to be tested as the concentration of the silicate standard solution.
[0023] Specifically, in a preferred embodiment, in step S2, the preparation method of the control solution is as follows: 10 ml, 20 ml, 30 ml, 40 ml, and 50 ml of silicate standard solution are added to the standard salinity matrix respectively to obtain control solution 1, control solution 2, control solution 3, control solution 4, and control solution 5 with silicate mass concentrations of 20 μg / mL, 40 μg / mL, 60 μg / mL, 80 μg / mL, and 100 μg / mL, respectively, which can obtain more accurate results.
[0024] In a preferred embodiment, in step S3, the linear regression equation uses the silicate mass concentration of the control solution as the abscissa and the peak area of its Raman spectrum as the ordinate, thereby directly linking the silicate mass concentration with the corresponding peak area of the Raman spectrum, which facilitates the subsequent determination of silicate content directly through the peak area of the Raman spectrum of the sample to be tested.
[0025] To further enhance the coffee ring effect of the solution, in a preferred embodiment, the substrate is a gold-plated glass slide, a molybdenum mirror, a stainless steel sheet, or an aluminum sheet.
[0026] In a preferred embodiment, the detection parameters of the Raman spectrometer are: a laser source of 785 nm, a laser power of 1200 mW, an exposure time of 1 second, and 25 exposures. Preferably, the Raman spectrometer operates in the range of 400–1250 cm⁻¹. -1 Scanning within the displacement range. The above spectral parameters are more suitable for determining the silicate content in the salt lake brine of this invention, enabling faster and more accurate content results.
[0027] The present application will be further described in detail below with reference to specific embodiments, which should not be construed as limiting the scope of protection claimed in the present application.
[0028] Example 1
[0029] Step S1: Obtain the brine from the salt lake to be tested. First, use CH-99 boron removal adsorption resin to remove boric acid and borates from the brine. Then, use an imprinted hydrogel with metal cations as template molecules to remove sodium from the brine. + Other metal cations, including at least Li + K + Ca 2+ Mg 2+ 、Sr 2+ and Rb + The solution to be tested was obtained;
[0030] Step S2: Determine the salinity value of the test solution and the content of its salt components. Then, prepare a standard salinity matrix with the same salinity value as the test solution using water and the same salt content. Prepare a silicate standard solution using the estimated silicate mass concentration of the brine in the test lake as the concentration of the silicate standard solution. Add 10 ml, 20 ml, 30 ml, 40 ml, and 50 ml of silicate standard solution to the standard salinity matrix, respectively, and shake thoroughly to obtain control solutions 1, 2, 3, 4, and 5 with silicate mass concentrations of 20 μg / mL, 40 μg / mL, 60 μg / mL, 80 μg / mL, and 100 μg / mL, respectively.
[0031] In step S3, control solutions 1 to 5 were dropped onto a stainless steel sheet substrate and evaporated at room temperature to obtain 5 control coffee rings. The 5 control coffee rings were scanned using a Raman spectrometer to obtain the peak area data of the 5 control Raman spectra: 121.7K, 243.4K, 365.1K, 468.8K, and 608.5K. The linear regression equation y = 5.995x + 1.8 was obtained by plotting the silicate mass concentration x of the control solution on the x-axis and the peak area y of its Raman spectrum on the y-axis.
[0032] Step S4: The solution to be tested is dropped onto a stainless steel sheet substrate and evaporated at room temperature to obtain the coffee ring to be tested. The coffee ring to be tested is scanned using a Raman spectrometer to obtain the Raman spectrum to be tested. The peak area of the Raman spectrum to be tested is substituted into the above linear regression equation to obtain the silicate content in the brine of the salt lake to be tested, as shown in Table 1.
[0033] The detection parameters for the Raman spectrometer were as follows: laser source at 785 nm, laser power at 1200 mW, exposure time at 1 second, and 25 exposures; the Raman spectrometer range was 400–1250 cm⁻¹. -1 Scan within the displacement range.
[0034] Comparative Example 1
[0035] Using the salt lake brine from Example 1, the silicate content was determined according to Part 4 of the "Marine Monitoring Standard" (GB 17378.4-2007): Determination of Silicates in Seawater Analysis, using the silicomolybdenum yellow spectrophotometric method. The results are shown in Table 1.
[0036] Table 1
[0037]
[0038] As can be seen from the above description, the embodiments of the present invention achieve the following technical effects: Firstly, boric acid, borates, and metal cations in the brine to be tested are removed using boron-removing adsorption resin and imprinted hydrogel. This reduces the interference of salinity and other substances on the detection results, simplifies the preparation process of the salinity matrix, and reduces the amount of reagents used. Furthermore, it fully combines the separation and enrichment characteristics of the coffee ring effect with the high-resolution detection of Raman spectroscopy. The detection results are similar to those of Comparative Example 1, which uses a more complex method, enabling rapid and accurate determination of the silicate content range in the brine.
[0039] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.
Claims
1. A method for determining the silicate content of a salt lake brine, characterized in that, The method comprises the following steps: Step S1, obtaining the to-be-tested salt lake brine, removing boric acid, borate and metal cations except Na + from the to-be-tested salt lake brine in sequence through a boron-removing adsorption resin and an imprinted hydrogel, to obtain a to-be-tested solution; Step S2, a standard salinity matrix with the same salinity value as the to-be-tested solution is prepared, and different volumes of silicate standard solution are added into the standard salinity matrix to obtain a plurality of control solutions with different silicate mass concentrations; Step S3, the control solutions are respectively dropped on a substrate, and a plurality of control coffee rings are obtained after evaporation at room temperature; the plurality of control coffee rings are respectively scanned by using a Raman spectrometer to obtain a plurality of control Raman spectra; and a linear regression equation is obtained according to the silicate mass concentrations of the control solutions and the peak areas of the Raman spectra of the control solutions; Step S4, the to-be-tested solution is dropped on the substrate, and a to-be-tested coffee ring is obtained after evaporation at room temperature; the to-be-tested coffee ring is scanned by using the Raman spectrometer to obtain a to-be-tested Raman spectrum; and the silicate content in the to-be-tested salt lake brine is obtained by substituting the peak area of the to-be-tested Raman spectrum into the linear regression equation.
2. The method of claim 1, wherein, In the step S1, the borate and the borate salt in the brine to be detected are removed by the boron-removing adsorption resin, and then the metal cations, including Li + , K + , Ca 2+ , Mg 2+ , Sr 2+ , and Rb + , in the brine to be detected are removed by the imprinted hydrogel using the metal cations as template molecules.
3. The method according to claim 1 or 2, characterized in that, In the step S1, the boron-removing adsorption resin is CH-99 boron-removing adsorption resin.
4. The method according to any one of claims 1 to 3, characterized in that, In the step S2, the standard salinity matrix is prepared by first measuring the salinity value of the to-be-tested solution and the content of salt components, and then using water and the same content of the salt components to prepare the standard salinity matrix.
5. The method according to any one of claims 1 to 4, characterized in that, In the step S2, the silicate standard solution is prepared by taking the estimated silicate mass concentration of the to-be-tested salt lake brine as the concentration of the silicate standard solution.
6. The method according to any one of claims 1 to 5, characterized in that, In the step S2, the control solutions are prepared by adding 10ml, 20ml, 30ml, 40ml and 50ml of the silicate standard solution into the standard salinity matrix respectively to obtain control solution 1, control solution 2, control solution 3, control solution 4 and control solution 5 with silicate mass concentrations of 20μg / mL, 40μg / mL, 60μg / mL, 80μg / mL and 100μg / mL respectively.
7. The method according to any one of claims 1 to 6, characterized in that, In the step S3, the linear regression equation takes the silicate mass concentrations of the control solutions as abscissa and the peak areas of the Raman spectra of the control solutions as ordinate.
8. The method according to any one of claims 1 to 7, characterized in that, The substrate is a gold-coated film glass slide, a molybdenum mirror, a stainless steel sheet or an aluminum sheet.
9. The method according to any one of claims 1 to 8, characterized in that, The detection parameters of the Raman spectrometer are as follows: the laser source is 785nm, the laser power is 1200mW, the exposure time is 1 second, and the exposure frequency is 25 times.
10. The method according to any one of claims 1 to 9, characterized in that, The Raman spectrometer scans over a displacement range of 400 to 1250 cm -1 -1.